DALRYMPLE, ALEXANDER (1737–1808), hydrographer to the admiralty, seventh son of Sir James Dalrymple, bart., auditor of the exchequer, and younger brother of Sir David Dalrymple, lord Hailes [q. v.], was born at New Hailes, near Edinburgh, on 24 July 1737. When he was fifteen years of age he received an appointment as writer in the East India Company's service, and sailed from England in December 1752. He arrived at Madras in the following May, and on account of his bad writing was put in the storekeeper's office, where he spent eighteen months without much prospect of advancement. Fortunately for him, when Mr. (afterwards Lord) Pigot came out as governor in October 1754, Dalrymple had been personally recommended to him. He had the lad removed to the secretary's office, and is said to have himself given him lessons in writing, to such good purpose that in a short time he could scarcely distinguish Dalrymple's writing from his own. It was at this time too that the youngster made the acquaintance of Orme the historian, then a member of council, who, pleased with his industry and intelligence, assisted him in his studies, and gave him the run of his library. In the course of a couple of years Dalrymple was appointed deputy-secretary, with the prospect of the secretaryship in succession, and was thus led to consider the possibility of extending the company's commerce to the eastward. In 1758 he obtained permission from the governor to go in the Cuddalore schooner on a voyage of observation among the Eastern Islands; but the siege of Madras by Lally (December 1758 to February 1759) postponed his voyage till the following April, when he took a passage to the Straits of Malacca in the company's ship Winchelsea, commanded by Mr. Thomas Howe, a brother of Lord Howe, from whose instruction he picked up some elementary knowledge of seamanship. In June he joined the Cuddalore in the Straits, and spent the next two years and a half cruising among the islands, effecting a very promising commercial treaty with the sultan of Sulu. Dalrymple returned to Madras in the end of January 1762, and in May he was appointed to command the London, a small vessel destined for opening the trade with Sulu. It appears that the governor at first intended to send a much larger ship, but that the smaller one was substituted at Dalrymple's instance, so that he might have the command. The change was unfortunate, for the London proved to be too small to carry the cargo which had been agreed for at Sulu, and the result of the voyage was disappointing. After a stay of two years among the islands, Dalrymple reached Canton in November 1764, and in the course of the following year returned to England, hoping to push, before the directors, some of the schemes on which the Madras government looked coldly. He did not, however, meet with more success at home; and a few years later published a couple of pamphlets as an appeal to the public: 1. ‘Account of what has passed between the East Indian Directors and Alexander Dalrymple,’ 8vo, 1769; and 2. ‘Plan for extending the Commerce of this Kingdom, and of the East India Company by an Establishment at Balambangan,’ 8vo, 1771. Meanwhile he had published ‘Account of Discoveries in the South Pacific Ocean before 1764,’ 8vo, 1767, which had made him acquainted with persons interested in the progress of discovery, and led to his being proposed as the commander of the expedition fitted out by government in 1768 at the request of the Royal Society, for the observation of the transit of Venus in 1769. To this appointment no objection would have been made; but Dalrymple insisted on having a commission as captain in the navy, such as had been granted to Halley [see Halley, John]. The instance was not a fortunate one, and Hawke, then first lord of the admiralty, refused; he referred to the trouble that had sprung up out of Halley's commission, and said he would suffer his right hand to be cut off before he would sign another of the same kind. Dalrymple was firm; so was Hawke, and the proposed appointment fell through, James Cook [q. v.] being eventually appointed to the command of the expedition. During the next few years Dalrymple devoted himself to geographical and hydrographical studies, and published in 1772 a chart of the northern part of the Bay of Bengal. He published also, in addition to several pamphlets on Indian affairs, an ‘Historical Collection of South Sea Voyages’ (2 vols. 4to, 1770–1), and an ‘Historical Relation of the several Expeditions, from Fort Marlborough to the Islands off the West Coast of Sumatra’ (4to, 1775). It was not till 1775 that he returned to Madras as a member of council, and then only for two years, when he was recalled on some charge of misconduct, the nature of which is not stated, but which proved to be groundless. In April 1779 he was appointed hydrographer to the East India Company; and in 1795, on the establishment of a hydrographic office at the admiralty, the appointment of hydrographer to the admiralty was offered to him. He accepted the offer, and held the appointment till 28 May 1808, when he was summarily dismissed in consequence, it is stated, of some offence caused by excess of zeal. Whatever this may have been, the dismissal preyed on Dalrymple's mind, and he died broken-hearted,’ just three weeks afterwards, on 19 June.

As the first to hold the post of hydrographer to the admiralty, Dalrymple's work was especially onerous and important, involving not only the collecting, collating, and publishing a large number of charts, but also the organising a department till then non-existent. This work he performed with industry and zeal, not always, perhaps, tempered by discretion. His services were unquestionably good, but he seems to have himself placed a higher value on them than his superiors for the time being did; and he was thus involved in frequent unpleasantnesses, and experienced frequent disappointments and mortifications, both at the admiralty and from the court of directors.

[European Magazine (November 1802), xlii. 323, with an engraved portrait, and a lengthy list of his publications, great and small; for which see also Catalogue of the British Museum; Naval Chronicle, xxxv. 177.]